Engine exhaust systems may use various injections of a reductant to assist in the reaction of various exhaust emissions. In one example, the reductant may include Diesel Exhaust Fluid (DEF), which may include a urea-based chemical reactant used in selective catalytic reduction (SCR) to reduce emissions of oxides of nitrogen in the exhaust of diesel vehicles. DEF may be stored in a storage vessel, such as a tank, on-board a vehicle. The DEF tank may be periodically refilled via a filler pipe coupled to the DEF tank so that DEF fluid may be available during engine operation.
Some automotive type fluid fill nozzles are made with non-standard or special features for various applications and may be inserted within a filler pipe for a DEF tank to refill the DEF tank with DEF. One such nozzle is the ZVA brand SCR urea nozzle made to ISO 22241 standards which has a magnetic interlock to prevent DEF from being pumped into fuel tanks. This nozzle has a change in diameter of the fill pipe to facilitate the use of the nozzle and to keep the magnetic interlock in the correct position to keep the lock in the magnetic field. The diameter change goes from 19 mm to approximately 24 mm with the step-up at a 45 degree angle.
The inventors herein have recognized that when such nozzles are placed in a filler pipe the nozzle may block the escape of air when the DEF tank is being replenished with DEF. By blocking the escape of the air, the nozzle can be pushed back and/or fluid and air may be blown out (spit back) in an uncontrolled manner leading to degradation in nozzle functionality and leakage of DEF fluid, for example.
In one example approach, in order to address these issues, a venting system for a filler pipe coupled to a diesel exhaust fluid tank in a vehicle is provided. The venting system comprises a plurality of cut-outs in an interior surface of the filler pipe along the interior diameter of the filler pipe in a top surface of the filler pipe.
In this way, air may be permitted to escape the DEF tank while the DEF tank is being replenished with DEF fluid via a nozzle disposed in the filler pipe, e.g., with a ZVA brand SCR urea nozzle as described above. Permitting air to escape during DEF refueling may reduce spit back and increase nozzle functionality, for example. Further, in such an approach a normal or standard sized filler pipe cap may be used to seal the filler pipe. Further still, in this approach, a seal on a special nozzle or fill bottle may seal on the end of the filler pipe during a DEF fluid refill event.
It should be understood that the background and summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.